Device for salvaging a marine or submarine engine

ABSTRACT

A device for salvaging a marine or submarine engine, this device comprising: a supple tie line ( 20 ) having a first end ( 21 ) to be connected to the engine ( 80 ), a bobbin ( 30 ) to which is connected a second end ( 22 ) of the supple tie line ( 20 ), the supple tie line being adapted to be wound around the bobbin, and a ballast charge ( 50 ) adapted to be combined with the bobbin ( 30 ). The bobbin ( 30 ) and the ballast charge ( 50 ) are such that the bobbin combined with the charge sinks, while the bobbin released from the charge floats; and the supple tie line ( 20 ) and the bobbin ( 30 ) cooperate such that the bobbin is released from the charge ( 50 ) by the unwinding of the supple tie line ( 20 ) wound around the bobbin ( 30 ).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Paris Convention Application of French Appl. No.1056656, filed on Aug. 18, 2010, which is incorporated by reference inits entirety.

TECHNICAL FIELD

The present disclosure relates to a device for salvaging a marine orsubmarine engine, and a marine or submarine engine equipped with such adevice.

In particular, said engine can be an autonomous submarine vehicle or AUV(for Autonomous Underwater Vehicle).

BACKGROUND

Installations for salvaging AUV in water from a ship are already known.These installations typically comprise a traction system for pulling theAUV via a cable connecting the traction system and the AUV.

Installation examples of this type are described in published patentapplications PCT No. WO 2008012472 and No. WO 2008012473.

In this type of installation, the cable is initially onboard the AUV.The first steps of salvaging the AUV consist of releasing the cable andwaiting until it deploys in the water. Once the cable is deployed, itcan be caught from the ship, for example by means of a harpoon or agrapple, and the free end of the cable (i.e. the end not connected tothe AUV) can be hauled back on board the ship. The cable can then beattached to the traction system.

Now, these first steps and, in particular, the deployment of the cablein the water, can be a problem. In fact, it happens that the cable doesnot deploy correctly and especially remains near the AUV. In this case,it can be necessary to bring the ship close to the AUV to pick up thecable, increasing the risk of collision between the ship and the AUV andtherefore the risk of damaging the AUV. It also eventuates that thecable can wind around some parts (ailerons, screw propeller, etc.) ofthe AUV, again increasing the chance of damaging the AUV.

There is therefore a need for a sure and simple solution for correctlydeploying the cable connected to the AUV.

SUMMARY

The present disclosure relates to a device for salvaging a marine orsubmarine engine, this device comprising a supple tie line having afirst end intended to be connected to said engine; a bobbin to which isconnected a second end of the supple tie line, the supple tie line beingadapted to be wound about the bobbin; and a ballast charge adapted to becombined with the bobbin. In this device, the bobbin and the ballastcharge are such that the bobbin combined with said charge sinks, whilethe bobbin released from said charge floats, and the supple tie line andthe bobbin cooperate such that the bobbin is released from said chargeby the unwinding of the supple tie line wound about the bobbin.

The methods of use and the advantages of such a device are thefollowing.

The bobbin, enclosed by the supple tie line and weighted by the ballastcharge, is previously onboard the marine or submarine engine. The typeof engine concerned is not limited and can be a floating engine or anengine in controlled immersion, and especially an AUV, a torpedo, asurface drone or another engine of similar architecture.

When the engine is to be salvaged from a salvaging base (e.g. a ship, awharf, an offshore platform, etc.), the bobbin is first released ordropped from the engine. The bobbin then sinks because of the ballastcharge. As it sinks, the bobbin brings along with it the supple tie linewhich unwinds as the bobbin goes down towards the bottom of the water.The unwinding of the supple tie line then prompts the release of thecharge and accordingly the unballasting of the bobbin. Advantageously,freeing the charge happens at the end of the unwinding of the supple tieline, i.e. this release is caused by the unwinding of the last turns ofthe supple tie line.

Once released from its ballast charge, the bobbin becomes floating (i.e.its density becomes less than that of water) such that it no longersinks, but instead floats to the surface. As the bobbin rises, theengine and the bobbin do not drift in the same way as they are notsubjected to the same conditions of wind and current. The result is thatthe bobbin moves away horizontally relative to the engine as it risesand the bobbin surfaces at a significant distance from the engine.

Due to the descent of the bobbin and the relative movement away from theengine, the supple tie line is correctly deployed and spaced apart fromthe engine, making later salvaging easier. Also, the risk of the suppletie line winding about the engine is limited. Finally, relative to theprior art, salvaging of the tie line, and therefore of the engine, iseasier and the risk of damaging the engine is less.

Supple tie line designates any type of sufficiently supple tie linewhich can be wound about the bobbin. This supple tie line must also besufficiently resistant to support traction forces exerted on it. Thesupple tie line is, for example, a cable or a cord. Advantageously, thesupple tie line is non-floating but sufficiently light so that thebehaviour of the supple tie line in water is controlled mainly by themovement of the bobbin and the optional first ballast element describedhereinbelow.

In certain embodiments, the supple tie line bears a first stop betweenits first and second ends, and the device also comprises at least onefirst ballast element configured to slide along the supple tie linebetween the first end and the first stop.

When the bobbin sinks, taking the tie line with it, the first ballastelement slides along the tie line until it comes into abutment againstthe first stop. In this way, the first ballast element exerts on thefirst portion of tie line located between the first end and the firststop a traction force directed downwards, which tends to keep this firstportion of tie line substantially vertical. The first ballast elementand the stop also form an articulation zone about which the secondportion of tie line, located between the first stop and the second endof the tie line, pivots when the bobbin rises to the surface. The factthat this articulation zone exists and is located at a certain distancebelow the engine further limits the risk of the tie line winding aboutthe engine. In particular, this risk remains limited even if the engineis running after deployment of the tie line.

In certain embodiments, the bobbin has a winding surface about which thesupple tie line can be wound, and the bobbin has a recess for receivingthe ballast charge, this recess having a first opening through which theballast charge can pass, this first discharge opening being located onthe winding surface.

In certain embodiments, the first opening is closed or blocked by afirst cover, the first cover having an external face defining a part ofthe winding surface.

In certain embodiments, the second end of the supple tie line isconnected to an attachment point located inside the recess, the suppletie line passes through the first cover, and the supple tie line bears asecond stop between its second end and the cover. This second stop pullsthe cover so as to unblock the first opening during unwinding of thesupple tie line. Unblocking the first opening then allows the ballastcharge to exit the recess and unballast the bobbin which will then riseto the surface.

In certain embodiments, the recess has a second opening through whichthe ballast charge can pass, this second opening being located outsidethe winding surface and closed or blocked by a second cover. The ballastcharge can be introduced inside the recess through this second opening.Since the cover is located outside the winding surface, placing andremoving the cover can be done independently of the winding of thesupple tie line about the bobbin. For example, this allows one tointroduce the ballast charge into the bobbin while the supple tie lineis already wound about the latter.

In certain embodiments, the bobbin bears at least one second ballastelement, this second ballast element being arranged on the bobbin so asto orient the first opening downwards, when the bobbin is under water.This helps to empty the recess of the ballast charge more easily andcompletely.

Another aim of the present disclosure is a marine or submarine engineequipped with a device such as described earlier, the first end of thesupple tie line being connected to said engine.

In certain embodiments, said engine is configured to take onboard thebobbin enclosed by the supple tie line, the engine comprising a releasesystem for releasing the bobbin.

In certain embodiments, the release system is remote-controlled. It canbe remote-controlled from the salvaging base of the engine, where thissalvaging base might be a ship, a wharf, an offshore platform, etc.

Several embodiments are described in the present disclosure. It isspecified however that, unless otherwise stated, the features describedin relation to one embodiment can be applied to another embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

The attached drawings are schematics and are not necessarily to scale;their main aim is to illustrate the principles of the invention.

In these drawings, from one figure (FIG.) to the other, similar elements(or parts of element) are identified by the same reference sign. Also,elements (or parts of elements) belonging to different embodiments buthaving an analogous function are identified by reference numerals spacedapart by 100, 200, etc.

FIG. 1 is a perspective view of an example of a device according to thepresent disclosure, comprising a bobbin and a supple tie line woundabout this bobbin.

FIG. 2 a sectional view of the device of FIG. 1, as per the sectionalplane II-II.

FIG. 3 is a sectional view, similar to that of FIG. 2, illustrating thebobbin before the ballast charge is introduced inside the bobbin.

FIG. 4 is a perspective view, illustrating the bobbin of FIG. 1 duringrelease of the ballast charge.

FIG. 5 is a sectional view of another example of a device according tothe present disclosure, comprising a bobbin and a supple tie line woundabout this bobbin.

FIG. 6 is a sectional view of the device of FIG. 5, as per the sectionalplane VI-VI, after unwinding of the supple tie line.

FIGS. 7 to 10 illustrate an example of an engine according to thepresent disclosure. These figures illustrate the successive steps of thedeployment of the supple tie line fitted to this engine.

FIG. 11 is a detailed view of the front part of the engine identified bythe circle XI in FIG. 7.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the device propose are described in detail hereinbelow,in reference to the attached drawings. These embodiments illustrate thecharacteristics and advantages of the invention. However, it is recalledthat the invention is not limited to these particular embodiments.

FIG. 1 illustrates an example of a device 10 for salvaging a marine orsubmarine engine 80. This engine 80 is shown in FIGS. 7 to 10.

The device 10 comprises a supple tie line 20 and a bobbin 30. The suppletie line 20 has two ends 21, 22. The first end 21 is connected to theengine 80, and the second end 22 is connected to the bobbin 30. In theexample, the supple tie line 20 is a cord.

The bobbin 30 comprises a central core 31 defining a winding surface 33for the tie line 20. This winding surface 33 is bordered by two flanges34, 35 which keep the tie line 20 between them. In this example, thecentral core 31 and one of the flanges 34 form a monobloc assembly. Theother flange 35 is fixed to the central core, for example by screwing(screw 36). It is to be noted that such a configuration has been chosento adjust the floatability of the bobbin, and the flange 35 made fromfloating material(s) is machined, for example, with variable dimensionsto vary the Archimedes thrust.

The central core 31 has a general shape of a hollow cylinder of axis A,with two openings at its axial ends, respectively blocked by two covers37, 38. The cover 37 is mounted, for example by screwing on the flange34 and cannot be dismantled. The cover 38 located to the side of theflange 35 blocks the opening 42 and is removable. The central core 31and the covers 37, 38, together define a recess 40.

This recess 40 takes up a ballast charge 50. This ballast charge 50 isformed by an assembly of elementary charges of limited size such as forexample metal balls, grains of sand, etc. In particular, the size ofthese elementary charges is clearly less than that of the openings 41,42 of the recess 40.

This ballast charge 50 is introduced inside the recess 40 through theopening 42, herein called “inlet opening”, as symbolised by arrow F1 ofFIG. 3. This is possible as the cover 38 is removable. Also, as theinlet opening 42 and its cover 38 are located outside the windingsurface 33 of the tie line 20, it is possible to place/remove the cover38 even when the cable 20 is wound about the bobbin 30. The ballastcharge 50 can therefore be introduced into the recess 40, through theinlet opening 42, after the winding of the cable 20.

The recess 40 also has another opening 41, herein called “dischargeopening”, through which the ballast charge 50 can exit the recess 40.This discharge opening 41 (see FIG. 4) is located on the winding surface33 and, in this example, it is closed or blocked by another cover 39whereof the external face 39A defines a part of the winding surface 33.

The supple tie line 20 and the bobbin 30 cooperate such that the bobbin30 is released from the charge 50 by the unwinding of the supple tieline 20 wound about the bobbin 30. More particularly, in this example,the unwinding of the supple tie line 20 causes displacement of the cover39 and therefore the unblocking of the discharge opening 41.

More precisely, the second end 22 of the tie line 20 is connected to anattachment point 44 located inside the recess 40. Also, the supple tieline 20 passes through the cover 39 and bears a stop 45 between itssecond end 22 and the cover 39. The stop 45 is, for example, a nodeobtained by interlacing of the tie line 20. The length of the tie line20 between its end 22 and the stop 45 is greater than the distancebetween the attachment point 44 and the cover 39 in its position closed.So, when the last turn of the tie line 20 unwinds, the tie line 20stretches and the second stop 45 pulls the cover 39, which unblocks thedischarge opening 41. The ballast charge 50 can then exit through theopening 41, as shown by arrow F2 in FIG. 4.

As the ballast charge 50 exits the recess 40 by gravity, via the opening41, it is preferable for this opening 41 to be oriented downwards asmuch as possible. For this purpose, several solutions, which can be usedalone or in combination, are proposed. One solution consists inproviding a discharge opening 41 highly extended circumferentially (forexample, more than 180°). Another solution consists in not positioningthe attachment point 44 of the supple tie line 20 in a positiondiametrically opposite the discharge opening 42 but instead positioningthe attachment point 44 near the discharge opening 41 and especially onthe same side of the axis A as the opening 41. Another solution consistsin mounting on the bobbin 30 one or more ballast elements 51, theseballast elements 51 being arranged on the bobbin 30 so as to orient theopening 41 downwards, when the bobbin is under water. In the example ofFIGS. 1 to 4, five ballast elements 51 in the form of a pin are fixed onthe flange 34 of the bobbin 30, on the same side of the axis A as thedischarge opening 41.

Another example of a device 110 is represented in FIGS. 5 and 6. As doesthe device 10, the device 110 comprises a supple tie line 120 and abobbin 130. The supple tie line 120 has two ends. The first end isconnected to a submarine or marine engine, and the second end 122 isconnected to the bobbin 130, at the level of an attachment point 144.

The bobbin 130 comprises a central core 131 defining a winding surface133 for the tie line 120. This winding surface 133 is bordered by twoflanges 134, 135 which keep the tie line 120 between them. In thisexample, the central core 131 and the two flanges 134, 135 form amonobloc assembly.

In this example, the central core 131 is not hollow. Yet it could be,especially for floatability reasons.

The bobbin 130 has a recess 140 for receiving a ballast charge 150. Thisballast charge 150 is a single piece such as, for example, a metal bar.

The recess 140 has the form of a groove made in the winding surface 133and, in the example, oriented parallel to the axis of the bobbin.

The ballast charge 150 is introduced in the recess 140 via the upperopening 141 of the groove. The “upper opening” is the opening locatedfacing the bottom of the groove. This upper opening 141 is located onthe winding surface 133. The ballast charge 150 is introduced in therecess 140 prior to the winding of the tie line 120 around the bobbin130.

The supple tie line 120 and the bobbin 130 cooperate such that thebobbin 130 is released from the charge 150 by the unwinding of the tieline 120. More particularly, in this example, it is the turns of the tieline 120 which keep the ballast charge 150 in the recess 140 andconsequently the unwinding of the last turns releases the ballast charge150 which can then slip out of the recess 140, as shown by arrow F3 inFIG. 6.

As the ballast charge 150 exits the recess 140 by gravity, via theopening 141, it is preferable for this opening 141 to be orienteddownwards as much as possible. For this purpose, several solutions,which can be used alone or in combination, are proposed. One solutionconsists of positioning the attachment point 144 of the supple tie line120 in a position diametrically opposite the opening 141, as shown inFIG. 6. Another solution consists of mounting on the bobbin 130 one ormore ballast elements, these ballast elements being arranged on thebobbin 130 so as to orient the opening 141 downwards, when the bobbin isunder water.

FIGS. 7 to 10 represent an example of an engine 80 according to thepresent disclosure. These FIGS. illustrate the successive steps of thedeployment of the supple tie line 20 fitted on this engine 80.

In the example, the engine 80 is an autonomous underwater vehicle orAUV. It is equipped with a device 10 of the type shown in FIGS. 1 to 4.Of course, it could be equipped with another type of device and,especially, with the device 110 of FIGS. 5 and 6.

The engine 80 is configured to be able to take onboard the bobbin 30enclosed by the supple tie line 20. For example, the engine 80 has inits front part, or <<nose>> 80A, a recess 82 for receiving the bobbin30, the tie line 20 and a ballast element 70 which also forms part ofthe device 10. The first end 21 of the tie line 20 is connected to thenose 80A of the engine 80, at an attachment point located inside or nearthe recess 82. The ballast element 70 is mounted to slide on the tieline 20.

The engine 80 also comprises a release system for releasing the bobbin30. This release system can have different structures and differentoperating modes which depend in particular of the way in which thebobbin 30 is initially connected to the engine 80 and on the shape ofthe recess 82. In the example, the recess 82 is closed by a trap 85 (seeFIG. 11) which can be opened by way of thrust means such as springs orjacks. In another example, the release system comprises an electromagnetwhich, when active, blocks the bobbin 30 inside its recess and which,when deactivated, releases the bobbin 30. Advantageously, the releasesystem is remote-controlled.

On completion of its mission, the engine 80 returns to the surface whereit is stopped (i.e. its propulsion means are stopped) or is stillmoving. Salvaging the AUV starts with releasing the bobbin 30 by usingthe release system remote-controlled from a distance, for example from aship (not shown).

The bobbin 30 then dives under the effect of gravity and the tie line 20unwinds in the water column located under the nose 80A of the engine 80,as shown by arrow F4 in FIG. 7. At the same time, the ballast element 70slides along the tie line 20 until it stops against a stop 71 shown byarrow F5 in FIG. 8. This stop 71 is located at a significant distancefrom the first end 21 of the tie line. For example, this stop is a nodeobtained by interlacing of the tie line 20.

After unwinding of the final turn of the cable 20, the cover 39 of thebobbin 30 opens and the ballast charge 50 is released, as shown in FIG.8. The bobbin 30 then becomes floating and rises to the surface, pullingwith it the tie line 20 as shown in FIG. 9. At the surface, the bobbin30 behaves like a drifting buoy. The bobbin 30 can then be caught andtaken on board the ship using different methods.

For example, one method consists in using a floating harpoon which isdragged by the ship on a cable. At the same time, the engine 80 moves insuch a way that the trajectory of the tie line 20 intersects that ofsaid cable. After intersection, the bobbin 30 is taken on board the shipby way of the cable and the harpoon.

Another method consists of approaching the engine 80 with the ship, theengine 80 idling or being stopped. When the ship is at a suitabledistance, a harpoon is launched from the bridge of the ship to catch thebobbin 30.

With respect to the behaviour of the assembly formed by the engine 80,the bobbin 30 and the tie line 20 in the water, after the bobbin isreleased, it is to be noted that, in the first instance, the devicefunctions in a water column. Next, once the ballast charge 50 isdropped, the bobbin rises to the surface. The bobbin 30 then driftsunder the action of deep-sea currents, while the engine 80 drifts underthe action of the wind and the surface sea current. The result is thatthe bobbin 30 arrives at the surface at a significant distance from theengine 80, achieving the goal in question.

When the bobbin 30 rises to the surface, the non-floating supple tieline 20 naturally tends to adopt the form of a small chain. The curve ofthis small chain is deformed by the ballast element 70. This ballastelement creates a point of inflection between a first portion 20A of thetie line 20, extending between the first end 21 of the tie line and thestop 71, and a second portion 20B of the tie line extending between thestop 71 and the second end 22. The ballast element 70 tends to orientthe first portion 20A as vertically as possible. This prevents the firstportion 20A of the tie line from rising to the surface near the bulk ofthe engine 80, in particular when the engine 80 is moving, as shown inFIG. 10. The presence of the ballast element 70 and its stop 71therefore clearly decreases the risk of seeing the tie line 20 becomingsnarled in the ailerons or in the engine screw 80.

1. A device for salvaging a marine or submarine engine, this devicecomprising: a supple tie line having a first end to be connected to saidengine, a bobbin to which is connected a second end of the supple tieline, the supple tie line being adapted to be wound around the bobbin,and a ballast charge adapted to be combined with the bobbin; in whichthe bobbin and the ballast charge are such that the bobbin combined withsaid charge sinks, while the bobbin released from said charge floats;and in which the supple tie line and the bobbin cooperate such that thebobbin is released from said charge by the unwinding of the supple tieline wound around the bobbin.
 2. The device of claim 1, wherein thesupple tie line bears a first stop between its first and second ends,and wherein the device also comprises at least a first ballast elementconfigured to slide along the supple tie line between the first end andthe first stop.
 3. The device of claim 1, wherein the bobbin has awinding surface around which the supple tie line can be wound, andwherein the bobbin has a recess for receiving the ballast charge, thisrecess having a first opening through which the ballast charge can pass,this first opening being located on the winding surface.
 4. The deviceof claim 3, wherein the first opening is blocked by a first cover, thefirst cover having an external face defining a part of the windingsurface.
 5. The device of claim 4, wherein the second end of the suppletie line is connected to an attachment point located inside the recess,wherein the supple tie line passes through the first cover, and whereinthe supple tie line bears a second stop between its second end and thecover in such a way that the second stop pulls the cover so as tounblock the first opening during unwinding of the supple tie line. 6.The device of claims 3, wherein the recess has a second opening throughwhich the ballast charge can pass, this second opening being locatedoutside the winding surface and being blocked by a second cover.
 7. Thedevice of claim 3, wherein the bobbin bears at least a second ballastelement, this ballast element being arranged on the bobbin so as toorient the first opening downwards, when the bobbin is under the water.8. A marine or submarine engine equipped with a device of claim 1, thefirst end of the supple tie line being connected to said engine.
 9. Themarine or submarine engine of claim 8, wherein the engine is configuredto take on board the bobbin enclosed by the supple tie line, the enginecomprising a release system for releasing the bobbin.
 10. The marine orsubmarine engine of claim 9, wherein the release system isremote-controlled.